20428880 has 20 divisors (see below), whose sum is σ = 47497332. Its totient is φ = 8171520.

The previous prime is 20428843. The next prime is 20428909. The reversal of 20428880 is 8882402.

It can be written as a sum of positive squares in 2 ways, for example, as 4999696 + 15429184 = 2236^2 + 3928^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 127601 + ... + 127760.

Almost surely, 2^20428880 is an apocalyptic number.

20428880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20428880 is an abundant number, since it is smaller than the sum of its proper divisors (27068452).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20428880 is a wasteful number, since it uses less digits than its factorization.

20428880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 255374 (or 255368 counting only the distinct ones).

The product of its (nonzero) digits is 8192, while the sum is 32.

The square root of 20428880 is about 4519.8318552796. The cubic root of 20428880 is about 273.3683212532.

The spelling of 20428880 in words is "twenty million, four hundred twenty-eight thousand, eight hundred eighty".